Himantolophus sagamius was described from a specimen taken off Japan in the early twentieth century. Since then the total known material has remained small, and the Natural History Museum of Los Angeles County and other institutions have treated each Californian stranding as an addition to a short list.
The rarity is a sampling artefact as much as a statement about abundance. Bathypelagic anglerfishes live in an enormous volume of water that is very poorly surveyed, and their soft bodies rarely survive the journey to a beach intact. A stranded specimen usually means an animal that died and drifted, not one that came inshore.
What the strandings do provide is material. Preserved footballfish have supported work on escal anatomy, on the bony spine-bearing plates in the skin, and on the extreme size difference between females and the much smaller males, which in this genus attach only briefly rather than fusing permanently as in some other ceratioids.